1. Field of the Invention
The present invention relates to animal containment systems, and, more particularly, to DGPS animal containment systems using a collar mounted receiver unit.
2. Description of the Related Art
Conventional and electric fencing is commonly used to control the location of animals. Barrier fencing, which physically blocks the movement of the animal is most frequently used to confine both domestic pets and farm animals. Physical electric fencing, which uses an electric shock to discourage contact with the fence, is typically used to confine commercial livestock. The purpose of an electric fence is to keep farm animals within an area, or to prevent undesired animals from entering the property. High voltage electrical impulses are applied to a “live” fence wire by an energizer. This impulse lasts only thousandths of a second but is repeated every second or so. An animal, which strays into contact with the live wire, completes a circuit between the live wire and the soil. The result is an electric shock sufficiently unpleasant to cause the animal to move rapidly away from the fence before the next electrical impulse. After a few encounters, animals learn not to touch the live wire or approach the fence too closely.
Electronic animal control systems are known in which a radio frequency receiver collar is attached to an animal to limit the movement of the animal to a predetermined area of confinement. The predetermined area is configured through the physical arrangement of a subterranean transmission antenna which transmits a unique electromagnetic signal produced by an operably linked transmitting device. The transmission pattern of the subterranean antenna creates zones of transmission or area “boundaries” in which the attached animal receiver collar is responsive to the uniquely transmitted electromagnetic signal. Upon entering a predetermined limit area, the receiver collar detects the unique electromagnetic signal and, in response, delivers a correction stimulus, such as a mild shock or audible signal, to the animal. The effect of the repeated stimulus teaches the animal, such as a dog, to avoid the limit areas thus confining the animal without use of physical fences or barriers.
Underground pet containment systems have been largely successful in removing unsightly physical structures from the landscape. However, unlike physical barrier systems they are not easily reconfigured. The installation of a subterranean transmission antenna requires excavation of the boundary area. This excavation can be further complicated in areas having immovable objects such as trees or in geographical areas subject to extreme weather conditions, such as areas in which the earth is frozen for extended durations of time. Additionally, excavation entails the disruption of plant root systems, damaging surrounding crops, grass, flower beds, or trees. As such, present underground systems are generally permanent to the property in which they are originally installed. Homeowners who relocate are often forced to purchase a second system rather than excavating and salvaging an old system.
Other animal containment systems using GPS technology are also known. For example, U.S. Pat. No. 6,043,748 (Touchton, et al.) discloses a GPS animal containment system having a receiver unit with a transceiver which receives GPS signals and retransmits the signals indicative of the location of the animal to a base station located in the home of the pet owner. The base station includes suitable processing circuitry for calculating the position of the animal within the containment area. The base station transmits a signal to the receiver unit worn by the animal for the application of a stimulus to the animal when the animal is approaching too close to the boundary.
What is needed in the art is a GPS animal containment system which succinctly applies stimulation to the animal based upon location and movement characteristics of the animal at any given point in time within the containment area.